The present invention relates to a copying process timing control system useful for an electrophotographic copying machine and, more particularly, to a copying process timing control circuit for a charger and a developing device in an electrophotographic copying machine.
Conventionally, a copying timing process control system for an electrophotographic copying machine is a pulse generation device. It includes a slit disc rotated in synchronization with the rotation of a photoreceptor, and a photosensor located at the position of receiving light passing through a slit of the slit disc. The output pulse of the pulse generation device is counted by a Central Processing Unit (CPU). When it counts at a predetermined count, any related unit to that count is activated or stopped.
To increase the accuracy of the copying timing process, the resolving power of the rotation angle of the photoreceptor should be increased. For this purpose, the following proposals with the resultant disadvantages may be considered:
(1) Increasing the number of slits formed in the slit disc: It may be disadvantageous that the diameter of the slit disc will become larger, thereby resulting in an increased size of the system.
(2) Increasing of the ration number of rotations of the slit disc per rotation of the photoreceptor: It may be disadvantageous that this alternative system makes it impossible for the slit disc to be directly attached to the photoreceptor without any rotation increasing member. This system will therefore be complicated.